1. Field of the Invention
The present invention relates generally to a self-locking and sealing ball plug that holds ball bearings and grease in position within a bearing race once installed, and which provides a visual aid to determine if the plug has been properly installed.
2. Description of the Prior Art
Plug seals for bearing races are well known in the prior art and assume a variety of shapes, sizes and degrees of design complexity. For example, there are many consumer and industrial applications where a swivel or other type rotary joint utilizes an internal bearing race which houses a series of ball bearings and grease. Swivel joints of this type are used for a broad range of applications in the petroleum, machine tool, chemical, refining, mining, distilling, brewing, and paint industries, as well as farm irrigation and fertilizing, and hundreds of OEM applications. Design, maintenance and plant engineers use swivel joints in flexible piping systems, loading arms, hose reels, sewer rodding and wastewater treatment equipment, and various types of process machinery. They are also widely used for machine tool coolant transfer, drum filling applications, and a variety of in-plant fluid and dry bulk transfer operations. Other common applications include hose reels, aviation refueling carts, hoses, steel mill cooling water lines, floating suction assemblies, floating roof drains, highway construction equipment, firefighting equipment, aviation ground support equipment and drum/tote fillers.
General purpose swivel joints are available from a large number of commercial sources, including to name a few, the FMC Chiksan® line, WECO Swivel Seals™, PPW Engineered Systems Swivel Seals™ and Scott Rotary Seals™.
Another common use of ball plugs is in the petroleum drilling industry. Many drill bit designs utilize a removable ball loading hole plug for plugging a ball bearing race where the ball bearing holds a rotary cutter on the bit body while allowing it to rotate. In this regard, see for example, the following exemplary patents: U.S. Pat. No. 4,445,791, to Klima; U.S. Pat. No. 2,676,790 to Turner; U.S. Pat. No. 1,779,587 to Childs; and U.S. Pat. No. 3,989,315 to Murdoch. All of these patented designs use some sort of ball plug to either temporarily or permanently plug a ball bearing race.
These are just two of a myriad of examples of ball bearing races in use in various commercial and industrial designs at the present time. However, despite the fact that such bearing race plugs have existed for many years, the common designs tend to be overly complex, or suffer from other disadvantages. For example, some of the prior art designs must be destroyed to be removed for grease replacement, or for repairing or replacing damaged bearing balls or to remove the companion part associated with the bearing race.
A need continues to exist, therefore, for a ball plug for a bearing race which is simple in design and economical to manufacture and which can be easily installed and removed by hand or with a simple tool, such as a pair of pliers.